Timing of downtown lights upsets Houston drivers

City continues to tinker with downtown traffic lights

Published 6:30 am, Wednesday, November 28, 2007

Houston officials are not ready to retreat on their efforts to improve the timing of downtown stoplights, despite some bad reviews from motorists.

Mayoral spokesman Patrick Trahan said Wednesday that the "cascading" or "progressive" system introduced last week in which lights change from red to green in sequence instead of several blocks at a time already is an improvement.

However, reader responses to a Nov. 21 Houston Chronicle story about the change have run more than 4-to-1 against the new timing. E-mails to traffic@chron.com have reflected similar views.

"Any plans to give up this dreadful light experiment yet?" wrote Pamela Parker.

"During the rush hours," wrote Jan Simpson, "traffic is backing up for blocks. Additionally, with the lane closures on Austin between Lamar and McKinney, it is taking three light cycles to go one block."

As adjustments continued today, a half-hour drive around downtown during the morning rush showed mixed results.

The cascading system worked beautifully this morning on Smith, Louisiana and Travis, although one sometimes had to shift lanes to avoid slowdowns caused by vehicles turning or stopped at the curb.

On the other hand, crosstown streets including Polk, Capitol and Preston were slow. These generally are narrower than the north-south streets, and their traffic has to contend with MetroRail trains and the fact that the major north-south streets get the most green time.

Except for the fact that speeds generally were slower in the morning rush (about 20 mph north-south), the observations mirrored those during the slack midafternoon traffic on Wednesday (when north-south streets ran nearly 30 mph). The timing is changed during the day to reflect traffic volume, Public Works engineers say.

Even though the system was not under stress, you could see both strengths and weaknesses. Smith, Louisiana, Milam, Travis, Fannin and San Jacinto all flowed smoothly. I got caught at a red light twice, both times because a motorist ahead had been slow to move when the lights changed.

East-west streets were a mixed bag. It was possible to drive all the way across downtown on Franklin, Congress, Preston, Texas and Pierce at about 15 mph while hitting, at most, two red lights. But progress was slow on Rusk and Walker.

When a light turned green, you could always make it through the next one, but the second light down the line was always red, often for 15 seconds or more.

That's expected, said Trahan, who compared the timing task to solving Rubik's Cube: any adjustment to one face of the cube affects the other faces as well.

"If you add time on a northwest-bound street," he said, "you're taking time away from an east-west street. There are going to be some streets (such as Walker and Rusk) that won't synch into the overall pattern."

And a long string of green lights comes at a cost, he noted: "If Louisiana and Milam and Travis are all green at the same time, that means people going east or west on, say, Bell, are seeing three reds in a row."

Even with little traffic on the streets, the smooth flow could be interrupted by a host of variables, and a driver had to be alert to change lanes to avoid these obstacles: A traffic lane disappears because of parked cars or construction, a driver up ahead is slow-poking or a pedestrian is in the crosswalk when he or she ought not be.

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Add the effects of the MetroRail trains on east-west traffic and police directing motorists out of garages during rush hour, and the system does not work the way it did an hour or so earlier.